test: add case for running CLI

Author: tomsquest

src/mediathequeroubaix/cli_test.py

@@ -0,0 +1,10 @@
+from typer.testing import CliRunner
+
+from mediathequeroubaix.main import app
+
+runner = CliRunner()
+
+
+def test_app():
+    result = runner.invoke(app, ["--help"])
+    assert result.exit_code == 0